15:01:10 RRSAgent has joined #tt 15:01:14 logging to https://www.w3.org/2023/04/27-tt-irc 15:01:14 RRSAgent, make logs Public 15:01:15 Meeting: Timed Text Working Group Teleconference 15:02:08 Present: Eric, Gary, Chris, Nigel, Cyril, Andreas 15:02:11 Chair: Gary, Nigel 15:02:13 scribe: nigel 15:02:41 atai has joined #tt 15:02:47 Previous meeting: https://www.w3.org/2023/04/13-tt-minutes.html 15:02:52 Agenda: https://github.com/w3c/ttwg/issues/249 15:03:08 Present+ Pierre 15:03:47 Present+ Chris_Flick 15:03:53 Present+ Chris_Needham 15:03:58 Present- Chris 15:04:18 Topic: This Meeting 15:04:49 Nigel: On the agenda today we have DAPT, IMSC-HRM CR, 15:05:03 .. WebVTT#512 (metadata) 15:05:05 Eric has joined #tt 15:05:08 .. and TPAC 2023 planning 15:05:20 .. Any other business or things to make sure we cover? 15:05:35 no other business 15:05:54 .. Anyone want to switch the order around? 15:06:32 Present+ James 15:06:43 no order changes 15:06:44 Topic: DAPT 15:07:05 Nigel: We published FPWD, thank you everyone 15:07:06 scribe+ cpn 15:07:09 jcraig has joined #tt 15:07:11 -> FPWD published at https://www.w3.org/TR/2023/WD-dapt-20230425/ 15:07:16 present+ 15:07:24 -> Blog post at https://www.w3.org/blog/news/archives/9896 15:07:44 rrsagent, make minutes 15:07:46 I have made the request to generate https://www.w3.org/2023/04/27-tt-minutes.html jcraig 15:07:53 Nigel: Some open issues to address 15:08:31 ... Atsushi is setting up auto-publication 15:08:42 ... We'll need to request horizontal and wide review, and address any comments 15:09:02 ... Shall I rebase open pull requests? 15:09:12 Cyril: Feel free to do it now, or I can next week 15:09:32 Nigel: Anything else to say on DAPT? 15:10:01 cpn_ has joined #tt 15:10:05 scribe+ cpn_ 15:10:09 Topic: IMSC HRM 15:10:29 Nigel: TAG review has been open a long time. I messaged Amy and Hadley to find out what's happening 15:11:16 ... We also need to sort out CR exit criteria. I proposed a change, want to make sure we think about it properly, given the charter changes 15:11:34 ... [reads current text] 15:11:45 ... I think one of each should be enough, without needing two of one 15:12:21 ... Either one content-producing implementation and one validating implementation or @@ 15:12:38 Pierre: I think that's a reasonable change 15:12:42 q? 15:13:21 Nigel: So let's go with that, in absence of TAG review 15:13:29 Pierre: I'd like to get a date for CR 15:13:46 Nigel: I suggested 8 weeks after publication 15:14:25 Pierre: As soon as we agree to publish, someone will modify it to reflect the actual publication date 15:14:37 Nigel: A feature request for respec? 15:14:48 ... Anything else on IMSC HRM? 15:15:04 Pierre: Should I ask Atsushi to pick a publication date, do we need a CfC? 15:15:21 Nigel: We will, but nervous about doing that without TAG review, as they're a horizontal review group 15:15:36 Pierre: They had comments, suggesting to make it a note 15:15:46 Nigel: I disagreed with that, then discussion stopped 15:15:56 Gary: They asked for clarification on what specifically needed review 15:16:02 Nigel: I replied to that in the issue 15:16:17 Gary: On making it a note is more of a personal thought than a TAG consensus 15:16:21 Present+ Eryk_Vershen 15:16:23 Nigel: I think so 15:17:22 Pierre: What's the right process? We can demonstrate review, let's say we're about to go to CR, set a date for them to do something 15:17:54 Nigel: This discussion is enough for me to go back to TAG, to say we're being held up 15:18:12 Pierre: Having a date makes it more concrete 15:18:32 Nigel: May 16? 15:18:36 Pierre: Sounds good 15:18:52 Nigel: Any more on this topic? 15:18:59 (nothing) 15:19:12 Topic: WebVTT issue 512 15:19:42 github: https://github.com/w3c/webvtt/issues/512 15:20:02 jcraig: There seems to be a negative response to #511, so should we close that? 15:20:13 .. This is on the ambiguity of metadata, and there being no path to know 15:20:17 .. if it is metadata or a caption. 15:20:29 .. I suggested either a JSON block or a URI, but others are using other types of metadata 15:20:33 .. so it is not always clear 15:20:37 q? 15:20:55 cpn_: I'm wondering what other alternative options for signalling the format we could think of. 15:21:12 Gary: I suggested a Metadata block akin to the Region block, should be backwards compatible. 15:21:23 .. I haven't tested that, but generally WebVTT says to ignore stuff you don't know about. 15:21:29 .. My main concern is backwards compat 15:21:41 .. General idea of having an in-file signal for the type of file is a valid request 15:22:02 jcraig: OK, I'll leave that one open and Eric and I will look into it more. 15:22:18 Gary: Do you want to give an overview of this proposal? 15:23:01 jcraig: Sure. [shares screen showing issue] 15:23:20 .. A few weeks ago Apple released the ability for Apple hardware devices like a Mac, AppleTV or iOS device 15:23:35 .. to automatically dim the screen by looking a few frames ahead at the flash patterns. 15:23:48 .. We released an open source library for this on GitHub as well. 15:23:59 .. The idea is to help anyone who has a negative reaction to the flashing, 15:24:10 .. as an alternative to only having a content warning. 15:24:22 .. We'd like to timecode where the flashing is. 15:24:37 .. We have an HLS proposal that Eryk V worked on. More information about that soon. 15:24:48 .. We would ideally like a way to specify the algorithm optionally. 15:25:01 .. In my VTT proposal it just says "level" without defining what that means. 15:25:19 .. If we were to include a test-uri and a test-version we could specify unambiguously what that level meant. 15:25:34 .. We could do a number of things with this, most obviously adjusting the timeline in some degree. 15:25:42 .. Like skipping over the flashes. 15:25:50 .. Thank you all who contributed to the discussion. 15:26:12 .. It seems like the general consensus is to not use WebVTT for this. 15:26:16 q+ 15:26:26 .. I'm not as familiar with WebVMT - Eric might want to add more context. 15:26:31 .. Happy to try to answer any more questions. 15:26:43 .. I know there were some HLS questions in the channel that haven't been answered yet. 15:26:48 ack cp 15:27:08 cpn_: WebVTT in terms of metadata is completely generic, and does not define any semantics 15:27:28 .. about metadata. WebVMT is an example for synchronising location and orientation data with video media. 15:27:38 .. It's a standalone specification that builds on top of WebVTT, 15:27:49 .. and defines the JSON object carried in the VTT file and its semantic. 15:28:00 .. The approach is to define it in its own specification as an application 15:28:07 .. rather than being in the WebVTT spec itself. 15:28:22 Gary: Yes, WebVMT also is a bit of a fork because it adds extra features to WebVTT. 15:28:32 .. If we go that route this metadata format would be simpler because it would not need 15:28:44 .. to redefine what WebVTT already defines, it would point to them directly. 15:28:59 q+ 15:29:13 Gary: I was asking about how it would be represented in HLS. 15:29:44 .. How do you put it in the manifest, and how do you represent it in the TextTracks object. 15:30:13 Eryk: We use the DATERANGE tag in HLS. For conveying this data we have a specific class 15:30:19 .. and an added attribute that denotes the risk. 15:30:26 .. That's it, in the multi-variant playlist. 15:30:40 jcraig: And the class mentioned is more or less the same as the type value. 15:30:48 Eryk: Yes, it's a little more verbose. 15:31:00 Gary: So the HLS wouldn't be a segmented version of this WebVTT? 15:31:04 jcraig: It's different. 15:31:08 Gary: That sounds fine. 15:31:25 jcraig: The similarity is the timecode and the level - the type would be equivalent but not the same. 15:31:46 .. We chose that because general flash and red flash definitions are common in WCAG so we could expand 15:31:49 .. it to that pattern. 15:32:04 Gary: It's exposed how HLS and Safari expose DATERANGE on the video element? 15:32:14 Eric: We expose DATERANGE as a data cue 15:32:22 Gary: That answers my questions. 15:32:27 q? 15:32:43 Nigel: Is this an Apple only feature, are other implementers interested? 15:33:12 James: We hope others will be interested, users seem to be excited about it, so we'd like to have other platforms benefit from the idea 15:33:40 ... And we'd like to enable it for Apple's services on other platforms, Android apps and TV+ content for Samsung TVs etc 15:33:57 Eryk: We'll be publishing it at the developers conference 15:34:10 q+ 15:34:30 Nigel: I'm supportive of the idea it should be a separate spec. A good approach could be to draft a spec for this, and try to get support 15:34:42 ... Consider whether it's a Rec track document or a Note 15:34:53 James: I'd defer to Eric or any of you on that 15:35:12 Eric: Not sure there's a benefit to it being on the Rec track, it's more work, and may not be a benefit to anyone else 15:35:24 Nigel: There's a lower bar for publishing a Note 15:35:58 ... A Note isn't normative, it doesn't carry any imprimatur of W3C as a whole, it's a document that people may find useful 15:36:18 ... We've used it for things that look normative, but things useful for industry more than things that are a recommendation 15:37:11 James: Would a Note be a link to an external document? 15:37:30 cpn_: A Note is its own document rather than a note within a different document. 15:37:38 jcraig: Yes. It's a W3C Document type 15:38:18 q+ EricC 15:38:23 Gary: You can't reference a Note normatively from a Rec 15:38:37 q+ 15:38:47 Nigel: The status of the document on a Note will say nobody should reference it normatively. 15:38:49 ack nigel 15:38:56 ack atai 15:39:03 pal has joined #tt 15:39:07 q+ 15:39:09 Andreas: That's definitely a good activity that I would support. 15:39:22 .. More generic question. We're discussing the syntax and the transport container. 15:39:30 .. Is there any more thought about a generic semantic model 15:39:35 .. that could be used for other formats. 15:39:47 .. Is the model already there? Or would it be useful to define it in a way that 15:39:53 .. could be used in other syntaxes or containers? 15:39:58 Gary: Like in IMSC? 15:40:02 Andreas: Yes 15:40:18 Eric: Do you mean specifically this kind of metadata or more generically to define a way to be able 15:40:26 .. to have other types of metadata in a VTT file? 15:40:32 Andreas: This specific flashing metadata 15:40:36 q? 15:40:49 jcraig: I'm not sure I fully understood that 15:41:10 .. We can dig into that 15:41:20 Andreas: It's independent of format, it's just a thought that this kind of information 15:41:32 .. would be structured specifically somewhere so it could be used regardless of format. 15:41:39 .. The semantics and expected behaviour could be similar. 15:41:51 jcraig: The data itself is not so complex that it would be difficult to do that transformation into other formats. 15:41:59 .. We're using it a different way in HLS. 15:42:17 .. I'm not opposed to a reusable structured format, that e.g. MPEG DASH could choose to implement, 15:42:33 .. using a format that this group defines, say, but I would not want a requirement to have a pass-through 15:42:46 .. format that would need to be supported. If we did want that we would need a Rec track document. 15:42:55 .. But a JSON block that can be used elsewhere, I'm all for that. 15:43:13 Eric: Or is the suggestion more to have a document that defines a value range, the elements of the metadata 15:43:29 .. so that in this case we could use it in JSON form, but it could also be used in XML form, pointing 15:43:37 .. back to a document that defines how to interpret them. 15:43:48 Andreas: Yes, thank you that's exactly what I had in mind. 15:44:01 jcraig: Seems reasonable to me. I don't think value should be defined in the transfer format 15:44:12 .. because it will be different depending on the algorithm that's used. 15:44:29 .. Apple's general flash algorithm outperforms Harding in some specific ways. 15:44:44 .. I could see there being multiple tracks, one using Harding, one the Apple open source algorithm, 15:44:50 .. another some other algorithm. 15:44:58 .. It's unlikely that anyone would ship all three. 15:45:06 .. The algorithm would define it, not the transport format. 15:45:08 q? 15:45:18 EricC: Do we have a document that defines these things for our new algorithm? 15:45:26 q- 15:45:35 ack Eric 15:45:51 Eric: If we do write up a Note or a Rec track document I don't think it needs to mention WebVMT. 15:45:57 .. It is just another type of metadata track. 15:46:12 OSS project https://github.com/apple/VideoFlashingReduction/ 15:46:33 jcraig: Posting some links here. The above is an algorithm. 15:46:56 .. There are also ePubs and PDFs that explain more, the first two links on the Whats New page: 15:46:59 https://developer.apple.com/accessibility/#whats-new 15:47:06 -> https://developer.apple.com/accessibility/#whats-new What's New Page 15:47:24 jcraig: The ePub embeds a video. 15:47:25 q? 15:47:30 ack cpn_ 15:47:41 cpn_: Coming back to the Note/Rec track question. 15:47:54 .. If this does become something more widely adopted across implementations, 15:47:56 Those are also linked in Issue 512 15:48:04 .. is there anything that prevents a Note from being promoted to the Rec track? 15:48:17 .. Once there are multiple implementations you would want the benefits of a Rec track. 15:48:30 jcraig: I can't think of anything that would prevent us from promoting a Note to a Rec 15:48:39 Nigel: Are there any IPR considerations here? 15:48:50 jcraig: Good question, I will have to get back to you on that one. 15:49:08 .. We did an IPR review before I posted this issue and the algorithm and open source project. 15:49:23 .. If it were within the TTWG it would be covered by the W3C patent policy. 15:49:53 Pierre: Whatever is submitted to this group (by members) is subject to the IPR policy. 15:50:00 .. There's an exclusion that starts with the FPWD. 15:50:30 q? 15:50:36 ack p 15:50:41 .. I've never heard that publishing a Note relaxes the constraints for a Rec track. 15:50:58 .. At a high level, a WG Note is a WG decision, really. The consensus body and review will be a lot 15:51:04 .. narrower than for a Rec track document. 15:51:13 .. You'll get much less attention, and there will be a lot less overhead. 15:51:26 s/TTWG it would be covered by the W3C patent policy./TTWG I think it would be covered by the W3C patent policy, but I will take a note to follow up internally./ 15:51:37 .. We talked about IPR. Typically, what I've mostly seen in Notes is application of existing standards 15:52:02 .. Something with its own applications, process and technology is typically better as a Rec track document. 15:52:10 .. I don't have a strong opinion, just trying to answer the question. 15:52:24 jcraig: Maybe the alternative is to take this as an incubator and not decide on Note or Rec track until 15:52:28 .. later in the process. 15:52:41 .. We can publish in WICG and bring into TTWG if that's the appropriate place for it to land. 15:52:47 Pierre: That's true too. 15:53:35 Nigel: WICG isn't the only place to incubate, can do in WG or another CG 15:53:47 ... We have a broad charter in terms of applications of timed text 15:54:09 James: Easier for us to participate where other organisations have joined already 15:54:35 Nigel: Publishing a Note in a WG is a bit like an incubation 15:55:35 James: My typical process in WICG is write in a wiki page, hence a reason to prefer that. The other benefit is you get people who are just interested in the one topic, which helps with organising meetings 15:55:55 Nigel: Any final thoughts on this topic? 15:56:05 James: Thank you all 15:56:43 SUMMARY: Apple to think about next steps for incubation 15:56:43 Nigel: In summary, Apple to think about next steps for incubation 15:56:43 Topic: TPAC 2023 planning 15:57:17 Gary: I did not submit the questionnaire yet. We have some time. 15:57:30 .. My main question is: we want to do the joint meetings with MEIG and MediaWG. 15:57:38 .. How much time do we want for TTWG itself? 15:57:50 .. I think we're probably more constrained because of the overlap with IBC. 15:58:34 Nigel: I would propose we allocate no more than 1 day for TTWG, which 15:58:46 .. could include joint meetings, and try to be efficient in the time that we get. 15:58:57 .. We normally go for 2 days but that's difficult for some. 15:59:14 cpn_: Would you want one joint meeting with MEIG and MediaWG or two separate joint meetings? 15:59:29 Gary: I'm not sure. One of the agenda topics we're thinking about is the TextTrack API, so having 15:59:35 .. the Media WG would be worth it there. 15:59:44 Nigel: Works for me. 15:59:57 cpn_: Sounds good. For MEIG I'm proposing we do a morning, and then have 16:00:02 .. agenda time allocated within that block. 16:00:16 .. I'm concerned that we request enough timeslots in the overall schedule so 16:00:29 s/general flash and red flash definitions/general flash, red flash, and spatial pattern definitions/ 16:00:31 .. the MediaWG joint meeting can be a dedicated session. Then if needed we can have time in the MEIG 16:00:40 .. session for any TTWG relevant agenda topics. 16:01:47 s/James: Would a Note be a link to an external document?/??? maybe ChristopherF?: Would a Note be a link to an external document?/ 16:01:51 Topic: Meeting close 16:02:02 Nigel: We're out of time for today. Thanks everyone, next call in 2 weeks. 16:02:29 .. Thanks to those who attend less often but came today - you're always welcome. 16:02:35 .. [adjourns meeting] 16:02:39 rrsagent, make minutes 16:02:41 I have made the request to generate https://www.w3.org/2023/04/27-tt-minutes.html nigel 16:03:45 s/Apple's general flash algorithm outperforms/we think Apple's general flash algorithm outperforms/ 16:04:08 s/.. Anyone want to switch the order around?/Nigel: Anyone want to switch the order around? 16:04:37 s/FPWD published at/FPWD 16:04:51 s/Blog post at/W3C Blog post 16:05:34 s/Either one content-producing implementation and one validating implementation or @@/Either one content-producing implementation and one validating implementation or two validating implementations 16:06:07 s/A feature request for respec?/A feature request for respec to specify relative dates? I might suggest that! 16:06:09 s/It's unlikely that anyone would ship all three./Though perhaps it's unlikely that a media publisher would want to support all three for and specific video. [Update: more likely when it is fully automated.]/ 16:07:05 s/cpn_/Chris_Needham/g 16:07:15 s/jcraig/James_Craig/g 16:08:23 rrsagent, make minutes 16:08:24 I have made the request to generate https://www.w3.org/2023/04/27-tt-minutes.html jcraig 16:11:06 s/James_Craig/James/g 16:11:52 s/EricC/Eric/g 16:12:35 s/What's New Page/Apple Accessibility What's New Page 16:13:49 rrsagent, make minutes 16:13:50 I have made the request to generate https://www.w3.org/2023/04/27-tt-minutes.html nigel 16:14:32 Present- jcraig 16:14:37 rrsagent, make minutes 16:14:39 I have made the request to generate https://www.w3.org/2023/04/27-tt-minutes.html nigel 16:15:43 s/Nigel: In summary, Apple to think about next steps for incubation// 16:15:52 scribeOptions: -final -noEmbedDiagnostics 16:15:54 rrsagent, make minutes 16:15:55 I have made the request to generate https://www.w3.org/2023/04/27-tt-minutes.html nigel 16:17:12 Regrets: Atsushi 16:17:12 rrsagent, make minutes 16:17:14 I have made the request to generate https://www.w3.org/2023/04/27-tt-minutes.html nigel 16:20:17 zakim, end meeting 16:20:17 As of this point the attendees have been Eric, Gary, Chris, Nigel, Cyril, Andreas, Pierre, Chris_Flick, Chris_Needham, James, jcraig, Eryk_Vershen 16:20:19 RRSAgent, please draft minutes v2 16:20:20 I have made the request to generate https://www.w3.org/2023/04/27-tt-minutes.html Zakim 16:20:26 I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye 16:20:26 rrsagent, excuse us 16:20:26 I see no action items 16:20:27 Zakim has left #tt